CES CES Blasting Operations & Techniques

Question 1

What is the primary purpose of a pre-blast inspection in surface blasting operations?

Accepted Answer

To identify nearby structures, utilities, and conditions that could be affected by the blast

Answer

To calculate the cost of the blasting operation

Answer

To determine the color-coding of detonators

Answer

To verify the blasting crew's lunch schedule

Question 2

In bench blasting, what does the term 'burden' refer to?

Accepted Answer

The perpendicular distance from the free face to the front row of blast holes

Answer

The weight of explosives loaded per hole

Answer

The total cost of explosives used

Answer

The delay interval between rows

Question 3

Which delay timing system minimizes flyrock and overbreak by allowing sequential detonation of blast holes?

Accepted Answer

Electric millisecond delay detonators or electronic detonators with programmed delays

Answer

Instantaneous initiation of all holes simultaneously

Answer

Detonating cord trunk lines with no delays

Answer

Manual fuse ignition in no particular order

Question 4

What is the recommended minimum stemming length above explosive column in a blast hole?

Accepted Answer

Equal to or greater than the burden distance

Answer

At least 10 feet regardless of hole diameter

Answer

One-half the drill depth

Answer

Stemming length is optional and varies by preference

Question 5

What does the term 'specific charge' (or powder factor) mean in blasting operations?

Accepted Answer

The weight of explosive used per unit volume or ton of rock broken

Answer

The sensitivity rating of the explosive

Answer

The charge per detonator used

Answer

The cost per pound of explosive

Question 6

In underground blasting, what is the function of a 'cut' in a round?

Accepted Answer

To provide a free face and void space so subsequent holes can break rock effectively

Answer

To mark the boundary of the tunnel perimeter

Answer

To designate holes loaded with detonating cord only

Answer

To indicate the location of the blasting machine